The multiple forms of bovine aorta lysyl oxidase of the purified multiple forms are being isolated and their physicochemical properties are under investigation. A stimulator of lysyl oxidase has been isolated from aorta. Small amounts of the compound activate the enzyme as much as 6 fold. The structure of this compound will be sought. Immunological studies of lysyl oxidase which have been run during the last year will be repeated using pure lysyl oxidase as an antigen. BIBLIOGRAPHIC REFERENCES: Shieh, J.J., Tamaye, R., and Yasunobu, K.T. (1975). Biochem. Biophys. Acta. Vidal, G.P., Shieh, J.J., and Yasunobu, K.T. (1975). Biochem. Biophys. Res. Commun. 64, 989.